As my dentist recommended, I would not go under. A lot of people I've talked to that have gone under, threw up after due to the anesthetic. It takes longer to recover if you do anesthetic.
It's not bad at all seriously... none of my 4 were out of the gums yet, and literally, he just numbed the gums, then gave a shot, I didn't feel anything. No laughing gas, No going under, just numbing, and it was fine. First tooth was out in like 5 seconds and I had to ask him if one was out lol.
Honestly though, the worst part of the operation is not during it, but after it. Choosing to go under or not isn't a big deal, you just recovery slightly faster if you don't. When the numbing wears off, it hurts really bad, so make sure... as SOON as they let you out of the office, to haul your *** to the nearest pharmacy and take those pain meds. It's very uncomfortable for like a day after you get them out... but it's not that bad.
They give you a lot of advice after like umm... I don't know yea that straw, and don't spit a lot or something, just make sure, oh and TRY not to play with your stitches.... it's hard, everyone does it lol.
Did anyone else's dentist give them the... "I have to tell you this because it's the law, but there is a really small chance that your mouth could be permanently numbed due to nerve damage" LOL sorry I bet that scared you